#if 0

#include <iostream>
#include <string>
using namespace std;

int main()
{
	string s1;
	char *s = "hello world";
	string s2(s);
	string s3(s2);
	string s4(10, 'a');
	cout << "s2=" << s2 << endl;
	cout << "s3=" << s3<<endl;
	cout << "s4=" << s4 << endl;
	system("pause");
	return 0;
}
#endif